The field and background of the invention herein are the same as those of the copending application which is incorporated herein by reference. A short summary thereof is included hereinafter.
The invention provides means for mounting printing cylinders which, although formed of very thin metal sleeves and readily collapsible, nevertheless are maintained in a relatively rigid condition in a printing press by means of air pressure.
The sleeves are electrodeposited metal such as nickel, copper, iron or other pure metal a fraction of a millimeter thick made by known processes such as described in U.S. Pat. No. 2,287,122. Sleeves of plated metal may be used such as for example, tin, chromium or other metals on nickel.
The method of utilizing the sleeves for printing is different from known methods where the pigment is forced through perforated designs in the sleeves because each sleeve is coated with a microthin coating of a photoconductive material of the type which is disclosed in U.S. Pat. No. 4,025,339. On this account the sleeves are imperforate.
The invention herein is directed to a structure which is simple and economical in construction. The problem of mounting the sleeve in a cylindrical configuration is solved in an elegant manner which provides for airtight clamping to a flanged disc at each end of an elongate framework. The framework is readily mounted in a printing press with the sleeve preinflated and/or capable of having the inflation maintained during use.
The invention herein also encompasses means for maintaining the pressure in the sleeve constant notwithstanding changes in temperature and even minor leaks during use and means for varying the circumference of the cylinder minutely by adjustment of internal fluid pressure during use. This latter capability enables the adjustment and refinement for repeat length during operation of the printing press.
The invention also contemplates novel structure coupling the framework to the press in a simple but highly effective manner and a system for using the sleeve of the invention.